Foot and Mouth Disease

April 2001
Brenda Heberling - Polk County Extension Livestock/4-H Agent

Eradicated in the United States in 1929?? So what is all the concern about? Foot and Mouth Disease (FMD) is an acute, highly communicable viral disease of cattle. It also affects pigs, sheep, goats, deer and other cloven hoofed animals.

FMD is caused by a virus with seven immunologically and serologically distinct types. Within each type there is a large number of strains that exhibit a spectrum of antigen characteristics; therefore, immunity to one type does not protect an animal against other types or strains. The virus is quickly inactivated outside of a pH range of 6.0 to 9.0 and by temperatures greater than 133 degrees F. Although, a residual virus may survive considerable time when associated with animal protein. For example, some of the FMD virus in infected milk will survive pasteurization at 167 degrees F for 15 seconds.

Transmission of the virus in generally by contact between infected and non-infected (susceptible) animals. Infected animals exhale large amounts of the virus, which can infect other animals through the respiration or oral routes. Wind and air currents can carry the virus for long distances. All excretions and secretions from an infected animal contain the virus and the virus may be present in milk and semen for up to four days before any symptoms are present. FMD has been transmitted from cow to calf via milk and milk tankers carrying infected milk have spread the disease between farms.

Transmission also occurs from ingestion of infected animal products; for example, hogs being fed infected milk or meat. The FMD virus can survive in dry fecal matter for 14 days in the summer, for up to 6 months in slurry in the winter, in urine for 39 days and on and in the soil for 3 days in the summer to up to 28 days in the winter. Transmission also occurs from contaminated clothes or footwear moving from farm to farm. The FMD virus is sensitive to acid and alkaline pH. So, sodium hydroxide, sodium carbonate and citric or acetic acid are effective as disinfectants.

The incubation period for FMD is 2 to 14 days depending on the conditions of the animal and the dose and strain of the virus. FMD has often been misdiagnosed as Vesicular Stomatitis and other vesicular diseases and IBR, BVD, Bluetongue MCF and Contagious Ecthyma. Following incubation, a fever of up to 106 degrees F (41 degrees C) develops. Painful blisters then erupt on the tongue, dental pads, gums, lips, above the hoof wall and between the hooves. Blisters can also be found on teats and udders and on areas of skin subject to trauma. Milk yields drop drastically in milking animals and all animals show a loss of condition and growth rate.

Foot and Mouth Disease

Adult animals have a mortality rate of about 5%, whereas, young animals have a mortality rate of about 75%. Recovered cattle may be carriers of FMD for 18 - 24 months.

There are numerous other effects of FMD in all animals. These effects include: salivation, drooling, lameness, mastitis, low conception rates and abortions. Recovery takes approximately two weeks in cattle.

Because FMD is one of the most difficult infections to control and the disease is found in many parts of the world, there is always a chance of a reintroduction into the United States. An outbreak would cost billions of dollars in lost production, loss of export market and loss of animals during eradication of the disease.

Due to the most recent major outbreak in France, the U.K. and Ireland the United States Department of Agriculture (USDA) has released a list of additional measures they are taking to guard against FMD. On March 13, 2001 the USDA announced that they are temporarily prohibiting the importation of swine and ruminants. Other actions include travelers from these countries identifying any farm contact.

Noted in all releases is that humans are not susceptible to the disease, they can transport the disease, but the economic consequences can be very devastating.

More information on FMD and traveling/vacationing information can be found on usda.gov.

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